Devices and methods of this kind which are known from the market are used, for example, in order to dry freshly painted workpieces, or even workpieces whose surface has been treated in some other way, in a drying oven. This should also be understood to include, in the present case, the stoning of powder coatings onto workpieces.
In the present case, vehicle wheels are mentioned as an example of the workpieces to be dried. However, the workpieces to be dried may also be other assemblies and components which may also be produced from non-metallic materials, in particular from plastic. If the components in question are fairly small parts, these may be accommodated in a carrying basket or the like which may be fastened to the workpiece-carrier.
In the case of drying ovens and methods which are known from the market for the purpose of drying vehicle wheels, it is usual for a number of vehicle wheels to arrive from a preceding treatment on a workpiece-carrier and then to be conveyed, also on the latter, through the dryer chamber. Under these circumstances, temperatures of, for example, about 180° C. prevail, at least in a drying zone.
After the vehicle wheels have passed through the dryer chamber and the drying process in the drying oven has been completed, the vehicle wheels are conveyed out of the dryer chamber again, together with the workpiece-carrier. This means that the workpiece-carriers are conveyed together with the vehicle wheels as they pass through the dryer chamber.
On each occasion, therefore, it is also necessary to heat up the workpiece-carrier with the vehicle wheels, or workpieces in general, that are to be dried, which workpiece-carrier also cools down again with the workpieces after passing through the drying oven.
Depending upon the ratio between the weight of the workpiece-carrier and the weight of the workpieces on said workpiece-carrier, a considerable portion of energy is consumed for the purpose of heating up the workpiece-carrier in the course of each drying operation, a fact which significantly impairs the overall energy balance of the drying device with respect to the workpieces to be dried, and thus increases the overall running costs of the installation.
It is therefore an object of the invention to provide a device and a method for drying workpieces of the kind initially mentioned, in which the energy balance is improved.